The present invention relates to electroactive polymers that are pre-strained to improve conversion from electrical to mechanical energy. When a voltage is applied to electrodes contacting a pre-strained polymer, the polymer deflects. This deflection may be used to do mechanical work. The pre-strain improves the mechanical response of an electroactive polymer. The present invention also relates to actuators including an electroactive polymer and mechanical coupling to convert deflection of the polymer into mechanical work. The present invention further relates to compliant electrodes that conform to the shape of a polymer. The present invention provides methods for fabricating electromechanical devices including one or more electroactive polymers.

Electroactive polymer transducers and actuators

The present invention relates to the mounting of pre-stressed electroactive material in such a manner that large displacement actuators or sensors result. The invention comprises mounting the pre-stressed electroactive material to a support layer. This combination of a pre-stressed electroactive material and support layer may in turn be attached to a mounting surface. The pre-stressed electroactive material may be a ferroelectric, pyroelectric, piezoelectric, or magnetostrictive material. The size, stiffness, mass, and material of the support layer is selected to result in the electroactive device having dynamic response properties, environmental capability characteristics, and the required resilience optimized for a given application. The capacity to connect the support layer to a surface expands the arenas in which the pre-stressed electroactive device may be used. Application for which the invention may be used include actuators, sensors, or as a component in a pumps, switches, relays, pressure transducers and acoustic devices.

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Advanced layered composite polylaminate electroactive actuator and sensor

An apparatus for measuring pressure within a conduit is disclosed preferably comprising a tube whose resonant frequency varies with the pressure of fluid within the tube; means for passing the fluid to be measured through the tube; two active piezoelectric films disposed in intimate contact with the tube on opposite sides thereof; first electronic means for energizing the first of the films to cause the tube to resonate at its natural frequency, and second electronic means connected to the other of the films to monitor the frequency of the tube.

Piezoelectric apparatus for measuring bodily fluid pressure within a conduit

An ultrasonic piezoelectric transducer device includes a transducer array consisting of an array of vibrating elements, and a base to which the array of vibrating elements in the transducer array are attached. The base include integrated electrical interconnects for carrying driving signals and sensed signals between the vibrating elements and an external control circuit. The base can be an ASIC wafer that includes integrated circuitry for controlling the driving and processing the sensed signals. The interconnects and control circuits in the base fit substantially within an area below the array of multiple vibrating elements.

Piezoelectric transducers using micro-dome arrays

A mechanical-to-acoustical transducer has at least one actuator, preferably a piezo motor, that is coupled, generally perpendicularly, to one edge of a diaphragm formed from a thin, flexible sheet material. The diaphragm is fixed at a point spaced from the actuator in the direction of its motion so that excursion of the actuator is translated into a corresponding, mechanically-amplified, excursion of the diaphragm—typically amplified five to seven times. The diaphragm is curved, preferably parabolically, and to a small degree. The diaphragm, if optically clear, can be mounted on a frame over a video display screen to provide a screen speaker. Preferably, such a screen speaker is pinned or adhered at upper and lower edges at or near its vertical centerline and is supported by and driven at both lateral edges by one or more single layer piezo actuators. The actuators are secured at one end to the frame or other stationary member, and at a free, movable end, to an edge of the diaphragm, generally at right angles. A gasket seals the edges of the diaphragm to maintain an acoustic pressure gradient across the diaphragm.

Mechanical-to-acoustical transformer and multi-media flat film speaker

An electro-acoustic transducer with a piezoelectric diaphragm supported by a support member having a curved portion for imparting a suitable resiliency and/or tension to said diaphragm to improve acoustic characteristics without reducing efficiency of the electro-mechanical conversion effected by the transducer.

Akihiko Kodama

Papers

Curved polymeric piezoelectric electro-acoustic transducer

Piezoelectric electro-acoustic transducer

Piezoelektrischer elektroakustischer wandler